Thread: Whats the difference

Determine the gyro stability factor (SG) of your bullets and firearm. Ask for this information when you purchase bullets. If the vendor does not know, there is a calculator that can help determine the SG.

Calculate drift with the following formula: drift = 1.25 x (SG + 1.2) x TOF ^ 1.83. Start by raising your time of flight to the power of 1.83. In the example, 1.9 raised to the power of 1.83 is 3.237. If the SG of our bullet and gun is 1.4, then the equation becomes: drift = 1.25 x (1.4 +1.2) x 3.237 for a result of 10.52. This means in this example, the bullet will drift 10.52 inches to the left or right depending on which twist the gun barrel has.

Found this.